Piston assemblies normally used are made of steel and various components of the piston assembly are hardened to increase their wear life. In the known piston assemblies, a slipper is pivotally connected to a piston so that one part can pivot relative to the other part. In most all known piston assemblies, a spherical cavity is in one of the components and a spherical ball is located on the other component. Upon assembly, the spherical ball is placed in the spherical cavity and retained therein by swaging a portion of the metal of the component having the cavity around a portion of the spherical ball to retain the spherical ball in cavity. In other applications, a snap ring is located in the cavity to retain the spherical ball in the spherical cavity. During operation of the known piston assemblies, they are subjected to large amounts of heat that is generated by the piston reciprocating in a bore of a barrel and the slipper sliding on the surface of a swashplate. With the large amount of heat being generated during operation, suitable clearance must be provided between the diameter of the piston and the diameter of the bore in the barrel so that they can move relative to one another without seizing, yet not allow execessive leakage. The wear rate between the piston and the barrel must be minimized to prevent loss of efficiency over a period of time and the piston and the bore in which it reciprocates must be precisely finished in order to reduce the sliding friction and/or wear therebetween. As is well known, it is beneficial to minimize the weight of the moving components in order to reduce their inertia.
The present invention is directed to overcoming one or more of the problems as set forth above.